Question: $ { {-3} \times \left[\begin{array}{rr}{-1} & {0} \\ {0} & {-2}\end{array}\right] = {?} } $
To multiply a matrix by a number, multiply each item of the matrix by the number. ${\left[\begin{array}{rr}{-3}\times{-1} & {-3}\times{0} \\ {-3}\times{0} & {-3}\times{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{3} & {0} \\ {0} & {6}\end{array}\right]}$